多点抽运光纤激光器速率方程组的近似解析解

Approximate analytical solutions to rate equations of multi-position-pumped fiber lasers

为了方便地对多点抽运光纤激光器的特性进行分析,采用保留上能级粒子再发射项主体部分的方法以提高精确度,解析求解了多点抽运掺镱光纤激光器的稳态二能级速率方程组,得到了光纤激光器的输出功率的近似解析解。并将输出功率的解析解与数值解进行了对比。结果表明,解析解与数值解差别小于5%。讨论了抽运光的利用效率与抽运点位置的关系,得到抽运源应该尽量靠近光纤端面的结论。同时,对比了单点抽运和多点抽运方案中抽运功率在光纤中的分布,可以看到,多点抽运时,抽运功率的分布较为均匀,能够缓解因包层对抽运光吸收引起的光纤局部过高的温升所造成的一系列问题,是实现大功率激光输出的良好选择。

In order to analyze the characteristics of multi-position pumped fiber laser expediently, the predominant part of the re-emission was adopted to improve the solutions precise, and the rate equations describing the Yb-doped multi-position pumped fiber lasers were solved analytically. The solutions of the output power of the fiber lasers were got approximately. Comparing the analytical solutions and the numerical solutions, the result shows the difference between them is small than 5%. Based on the relationship between the position of the pump point and the utilization efficiency of pump light, the conclusion was drawn that pump sources should be set near the fiber ends. Simulating the distribution of pump light along the fiber of the two schemes（one-position-pump and multi-position-pump）, the results show that for the multi-position-pump scheme, the distribution of pump power is relatively uniform along the fiber compared to that of the one-position-pump scheme. In other words, extra local temperature rise arising from the absorption of the external cald can be reduced in the multi-position-pump scheme, rendering it a better choice for the high power fiber lasers.